1. Introduction
The Fluke 789 ProcessMeter is a versatile maintenance and calibration tool designed for instrumentation technicians. It integrates the capabilities of a Digital Multimeter (DMM) with a loop calibrator into a single, rugged, handheld device. This instrument allows for the measurement, sourcing, and simulation of 4-20 mA DC loop current signals with high accuracy, and includes a built-in 24 V loop supply.
2. Safety Information
Always adhere to safety precautions when operating the Fluke 789 ProcessMeter. This device is designed to protect users in high-voltage, high-current environments. Failure to follow safety guidelines can result in serious injury or damage to the equipment.
- Overload Protection: The device features 1000V overload protection on V, Ohms, and frequency functions, and 150V overload protection on mA, backed by a 440 mA 1000V fuse.
- Safety Standards: The Fluke 789 meets 1000V EN61010-1 CAT III standards and 600V EN61010-1 CAT IV standards.
- Physical Durability: The unit has passed a one-meter drop test, indicating its robust construction.
- Battery Safety: Ensure correct battery polarity and use only specified battery types. Replace batteries in a safe environment.
3. What's in the Box
Upon unpacking your Fluke 789 ProcessMeter, verify that all the following items are included:
- Fluke 789 ProcessMeter
- 1 Set of AC175 Alligator Clips
- 1 Set of TL71 Test Lead Set
- 4 AA 1.5 V Alkaline Batteries (installed)
- Quick Reference Guide
4. Product Overview
The Fluke 789 ProcessMeter combines a digital multimeter with a loop calibrator. Below is an overview of its key features and components.
Image Description: A front view of the Fluke 789 ProcessMeter, highlighting its main features with numbered callouts. The yellow device has a large digital display showing '8.000 mA DC' and '25.0 % LOOP POWER HART'. A rotary dial is central, surrounded by various function buttons. Test lead inputs are at the bottom. The numbered callouts point to: 1. Full multimeter capabilities, 2. Wireless communication (implied by Fluke Connect logo), 3. Full 4-20 mA troubleshooting, 4. mA Auto ramping and stepping, 5. Built-in HART resistor, 6. Integrated 24 V loop power, 7. Safety rated.
Image Description: A clear, detailed front view of the Fluke 789 ProcessMeter. The device is yellow with a grey display and black buttons and rotary switch. The display shows '8.000 mA DC' and '25.0 % LOOP POWER HART'. The rotary switch is set to the 'OFF' position. Various buttons for functions like '100% SpanCheck', 'MIN MAX', 'RANGE', 'HOLD', '0%', '%STEP', 'COARSE', 'FINE', 'REL Δ', and 'Hz' are visible. Input jacks are at the bottom.
Key Components:
- Large Dual Display: Features enhanced backlight with two brightness settings for clear readings.
- Rotary Switch: Selects measurement and output functions.
- Function Buttons: Control specific features like range, hold, min/max, step, and ramp.
- Input Jacks: For connecting test leads for various measurements.
- Output Jacks: For sourcing and simulating current.
5. Setup
Battery Installation
The Fluke 789 ProcessMeter operates on four AA 1.5V alkaline batteries, which are included and pre-installed. The battery compartment is externally accessible for easy changes.
- Ensure the device is powered off.
- Locate the battery compartment cover on the rear of the unit.
- Use a Torx driver to loosen the screws securing the battery cover.
- Remove the cover and replace the old batteries with new AA 1.5V alkaline batteries, observing correct polarity.
- Securely reattach the battery cover and tighten the screws.
Connecting Test Leads
Connect the supplied TL71 Test Lead Set and AC175 Alligator Clips to the appropriate input jacks at the bottom of the ProcessMeter for your desired measurement or output function.
6. Operating Instructions
The Fluke 789 ProcessMeter offers a wide range of functions for electrical measurement and process loop calibration. Always refer to the quick reference guide for detailed operational steps for specific tasks.
General Operation
- Power On/Off: Rotate the central switch from 'OFF' to the desired function to power on the device. Return to 'OFF' to power off.
- Backlight: Press the backlight button (sun icon) to adjust display brightness.
- Hold Function: Press the 'HOLD' button to freeze the current display reading. Press again to release.
- Min/Max: Press 'MIN MAX' to record minimum and maximum values over time.
DMM Capabilities
The 789 ProcessMeter includes standard DMM functions:
- Voltage (AC/DC) measurement
- Resistance measurement
- Frequency measurement
- Continuity and Diode test
4-20 mA Loop Calibration
The device excels in measuring, sourcing, and simulating 4-20 mA signals.
- Current Measurement Range: 0 to 30 mA DC.
- Sourcing/Simulating: Provides 0.05% accuracy and 1 microamp resolution for DC loop current.
- 24V Loop Power Supply: Built-in supply reduces the need for external power when testing transmitters offline.
- HART Resistor: Includes a built-in, selectable 250-Ohm HART resistor.
- mA Output Control: Features 25% Manual Step, Auto Step, and Auto Ramp functions.
- Span Check: Use the '0%' and '100%' buttons to quickly toggle between 4 mA and 20 mA sourcing for a rapid span check.
7. Maintenance
Proper maintenance ensures the longevity and accuracy of your Fluke 789 ProcessMeter.
Cleaning
- Wipe the case with a damp cloth and mild detergent. Do not use abrasives or solvents.
- Clean the input jacks periodically to prevent poor connections.
Battery Replacement
Refer to the 'Battery Installation' section under 'Setup' for detailed instructions. Replace batteries when the low battery indicator appears on the display.
Fuse Replacement
The 789 ProcessMeter has a 440 mA 1000V fuse for mA input protection. If the mA function stops working, the fuse may need replacement. Fuse replacement should only be performed by qualified personnel following the instructions in the full service manual.
8. Troubleshooting
This section provides solutions to common issues encountered with the Fluke 789 ProcessMeter.
| Problem | Possible Cause | Solution |
|---|---|---|
| Meter does not power on | Dead or incorrectly installed batteries | Replace batteries, ensuring correct polarity. |
| No mA reading or output | Blown mA fuse | Replace the mA fuse (refer to Maintenance section). |
| Inaccurate readings | Dirty test leads or input jacks; environmental factors | Clean test leads and jacks. Ensure stable operating environment. Consider professional calibration if issues persist. |
| Display is dim or unreadable | Low battery; backlight setting | Replace batteries. Adjust backlight brightness using the backlight button. |
9. Specifications
Detailed technical specifications for the Fluke 789 ProcessMeter.
| Feature | Specification |
|---|---|
| Model Number | 789 |
| Dimensions (H x W x D) | 9.02 x 15.2 x 2.99 inches |
| Item Weight | 1.34 Pounds (600 grams) |
| Power Source | Battery Powered |
| Batteries | 4 AA 1.5V alkaline batteries (included) |
| Typical Battery Life (Measurement) | Approximately 140 hours |
| Typical Battery Life (Sourcing 20 mA) | Approximately 10 hours |
| Current Measurement Range | 0 to 30 mA DC |
| mA Source Accuracy | 0.05% |
| mA Source Resolution | 1 microamp |
| Loop Power Supply | 24V |
| HART Resistor | Built-in, selectable 250-Ohm |
| Overload Protection (V, Ohms, Freq) | 1000V |
| Overload Protection (mA) | 150V (440 mA 1000V fuse) |
| Safety Rating | 1000V EN61010-1 CAT III, 600V EN61010-1 CAT IV |
10. Warranty and Support
Warranty Information
Fluke products are designed for reliability and durability. This product is covered by a manufacturer's warranty. For specific warranty terms and conditions, please refer to the documentation included with your purchase or visit the official Fluke website. Ensure your purchase is from an authorized distributor to guarantee a valid warranty.
Customer Support
For technical assistance, troubleshooting beyond this manual, or service inquiries, please contact Fluke customer support. Contact information can typically be found on the Fluke website or in the quick reference guide provided with your device.
